The Millstone nuclear power facility in Waterford, Conn. is shown. Climate change and extreme weather already are causing disruptions in the U.S. energy supply that are likely to worsen as more intense storms, higher temperatures and more frequent droughts occur, the government says in a new report.

WASHINGTON — Climate change and extreme weather already are causing disruptions in the U.S. energy supply that are likely to worsen as more intense storms, higher temperatures and more frequent droughts occur, the government says in a new report.

The report, released Thursday by the Energy Department, says blackouts and other problems caused by Superstorm Sandy and other extreme weather events are likely to be repeated across the country as an aging energy infrastructure struggles to adapt to rising seas, higher storm surges and increased flooding. A range of energy sources are at risk, from coal-fired power plants to oil wells, hydroelectric dams and nuclear power plants.

Climate-related disasters have already costs tens of billions of dollars, and the report says costs could grow exponentially unless a more comprehensive and accelerated response is adopted.

On the Gulf Coast, for instance, the report cites a study by an energy company and wetland foundation projecting that by 2030, nearly $1 trillion in energy assets in the region will be at risk from rising sea levels and more intense hurricanes. Based on an analysis of hazards, assets and vulnerabilities, the Gulf Coast energy sector faces an average annual loss from climate change and extreme weather of $8 billion in 2030, the report said.

The report urges private companies, governments and research institutions to take action to further understand the risks of climate change and reduce them. The report does not offer immediate recommendations, but says power plants and oil companies should use less water and recycle what they use.

Electricity providers should harden transmission grids and build emergency backup systems, the report says, and operators of hydroelectric dams should improve turbine efficiency. The report also recommends that governments and utilities work together to reduce demand for electricity.

“Water is obviously the big question,” said Jonathan Pershing, deputy assistant secretary of energy for climate change policy and technology, who oversaw the report. “In drought you don’t have enough water. As seas rise, you have too much.”

While the risks from drought, floods and hurricanes are clear, water plays an important role in less obvious ways as well, Pershing said. Both coal-fired and nuclear power plants, for instance, need large volumes of water for cooling. As temperatures rise, that becomes more difficult.

The report cites several examples from 2012, the hottest year in the United States since record-keeping began in 1895:

In August, a nuclear power station in Connecticut shut down one reactor because the temperature of the intake cooling water, withdrawn from Long Island Sound, was too high. The two-week shutdown resulted in the loss of 255,000 megawatt-hours of power, worth several million dollars, the report said.

In the Midwest, drought and low river water depths disrupted the transportation of commodities, such as petroleum and coal, delivered by barges along the Mississippi River.

In California, reduced snowpack in the Sierra Nevada mountains limited hydroelectric power generation capacity by about 8 percent.

“Costs are already happening and it’s getting worse,” Pershing said. “We are seeing damages across all parts of the energy sector.”

Rising heat in the West will drive a steep increase in demand for air conditioning, which has already forced blackouts and brownouts in some places, the report said. The Energy Department’s Argonne National Laboratory found that air conditioning demand in the West will require 34 gigawatts of new electricity generating capacity by 2050, equivalent to the construction of 100 power plants.

The report sends a “significant message about the risks and vulnerabilities” facing the U.S. energy sector, Pershing said. It should provide a blueprint for states and municipalities to consider, along with utilities and other energy providers and even consumers, who can do their part by reducing energy use or seeking alternative forms of energy, he said.

The report is the first of many to be produced across a range of economic sectors as the Obama administration responds to climate change and makes recommendations, Pershing said.

President Barack Obama announced a wide-ranging plan last month to combat global warming. The plan for the first time would put limits on carbon pollution from new and existing power plants as well as boost renewable energy production on federal lands, increase efficiency standards and prepare communities to deal with higher temperatures.